Creating a csv file

private void create_csv(DataTable dt, string fname)

        {

            //if (string.IsNullOrEmpty(fname))

            //{

            //    fname = Application.StartupPath + "\\pdftemplate_" + DateTime.Now.Ticks + ".csv";

            //}

            //else { fname += ".csv"; } fullfilename = fname;

            //FileInfo f = new FileInfo(fname);

            //try

            //{

            //    if (f.Exists)

            //    {

            //        f.Delete();

            //    }

            //}

            //catch { f.Delete(); }

            fname = GenarateFilename(fname, ".csv");

            fullfilename = fname;

            FileStream fs = new FileStream(fname, FileMode.CreateNew, FileAccess.Write);

            StreamWriter sw = new StreamWriter(fs);

            StringBuilder sb = new StringBuilder();

            try

            {

                //first line coloumn names

                for (int i = 0; i < dt.Columns.Count; i++)

                {

                    sb.Append("," + dt.Columns[i].ColumnName.ToString());

                }

                sw.WriteLine(sb.ToString().Substring(1));

                sb.Length = 0;

                // insert datarows in csv file

                foreach (DataRow dr in dt.Rows)

                {

                    for (int i = 0; i < dt.Columns.Count; i++)

                    {

                        sb.Append("," + dr[i].ToString());

                    }

                    sw.WriteLine(sb.ToString().Substring(1));

                    sb.Length = 0;

                }

            }

            catch { }

            finally

            {

                sw.Flush();

                sw.Close();

                fs.Close();

                fs.Dispose();

                sb = null;

            }

        }